Conventionally, there is known a sterilization and disinfection apparatus for a food or the like, which uses heated water vapor, for example (see WO 2004/068003). Specifically, a object to be heated comprising a plurality of balls or the like is filled in a cylindrical body, water-jet is supplied to one side of the cylindrical body, and heated water vapor is squirted from the other side of the cylindrical body by high-frequency induction heating of the object to be heated via an exciting coil that wraps around the periphery of the cylindrical body. An apparatus by which this heated water vapor is sprayed into a food or the like to perform sterilization and disinfection is described.
In addition, in the fields of processed foods, supplements, drugs, quasi drugs, cosmetics, feeding stuff, and the like containing an oily ingredient such as edible oils, unsaturated fatty acids, phospholipids, and fat-soluble vitamins, antioxidative strategies using various antioxidative substances in manufacturing steps or packages have been investigated for controlling oxidation of the oily ingredient. As examples of these antioxidative methods, a method of adding hydroxy acid (see Japanese Patent Application Laid-Open No. Hei 07-258682), a method of adding soy sauce oil produced as a byproduct in the process of brewing soy sauce (see Japanese Patent Application Laid-Open No. Hei 11-012592), a method of adding α-lipoic acid so as to impart antioxidative property (see Japanese Patent Application Laid-Open No. 2008-013630), and the like have been investigated.
On the other hand, as for water vapor plasma, it has been investigated to use water vapor plasma for processing exhaust gas (see Japanese Patent Application Laid-Open No. Hei 6-343820), or for decomposing organic halogen (see Japanese Patent Application Laid-Open No. Hei 9-262459). However, the water vapor plasma used as above was unstable, or center temperature in the plasma was very high with 10,000 degrees centigrade. In addition, it has been investigated to use water vapor plasma for etching (see Japanese Patent Application Laid-Open No. 2001-308070), but it uses a conventional method of generating plasma between electrodes, which has a problem in supplying plasma stably. In addition, it has been investigated to generate plasma by adjusting pressure and voltage to be predetermined values so as to use the plasma for sterilizing medical appliances or the like (see Japanese Patent Application Laid-Open No. 2008-188032), but the apparatus cannot be applied to a food or the like.